mirror of
https://github.com/AsahiLinux/u-boot
synced 2024-11-12 07:57:21 +00:00
34e452dd02
Currently all shell command docs are put in the doc/usage root. Let's group them into cmd/ sub-directory. Signed-off-by: Bin Meng <bmeng.cn@gmail.com> Reviewed-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
94 lines
2.5 KiB
ReStructuredText
94 lines
2.5 KiB
ReStructuredText
.. SPDX-License-Identifier: GPL-2.0+
|
|
|
|
mbr command
|
|
===========
|
|
|
|
Synopsis
|
|
--------
|
|
|
|
::
|
|
|
|
mbr verify [interface] [device no] [partition list]
|
|
mbr write [interface] [device no] [partition list]
|
|
|
|
Description
|
|
-----------
|
|
|
|
The mbr command lets users create or verify the MBR (Master Boot Record)
|
|
partition layout based on the provided text description. The partition
|
|
layout is alternatively read from the 'mbr_parts' environment variable.
|
|
This can be used in scripts to help system image flashing tools to ensure
|
|
proper partition layout.
|
|
|
|
The syntax of the text description of the partition list is similar to
|
|
the one used by the 'gpt' command.
|
|
|
|
Supported partition parameters are:
|
|
|
|
* name (currently ignored)
|
|
* start (partition start offset in bytes)
|
|
* size (in bytes or '-' to expand it to the whole free area)
|
|
* bootable (boolean flag)
|
|
* id (MBR partition type)
|
|
|
|
If one wants to create more than 4 partitions, an 'Extended' primary
|
|
partition (with 0x05 ID) has to be explicitly provided as a one of the
|
|
first 4 entries.
|
|
|
|
Here is an example how to create a 6 partitions (3 on the 'extended
|
|
volume'), some of the predefined sizes:
|
|
|
|
::
|
|
|
|
=> setenv mbr_parts 'name=boot,start=4M,size=128M,bootable,id=0x0e;
|
|
name=rootfs,size=3072M,id=0x83;
|
|
name=system-data,size=512M,id=0x83;
|
|
name=[ext],size=-,id=0x05;
|
|
name=user,size=-,id=0x83;
|
|
name=modules,size=100M,id=0x83;
|
|
name=ramdisk,size=8M,id=0x83'
|
|
=> mbr write mmc 0
|
|
|
|
To check if the layout on the MMC #0 storage device matches the provided
|
|
text description one has to issue following command (assuming that
|
|
mbr_parts environment variable is set):
|
|
|
|
::
|
|
|
|
=> mbr verify mmc 0
|
|
|
|
The verify sub-command is especially useful in the system update scripts:
|
|
|
|
::
|
|
|
|
=> if mbr verify mmc 0; then
|
|
echo MBR layout needs to be updated
|
|
...
|
|
fi
|
|
|
|
The 'mbr write' command returns 0 on success write or 1 on failure.
|
|
|
|
The 'mbr verify' returns 0 if the layout matches the one on the storage
|
|
device or 1 if not.
|
|
|
|
Configuration
|
|
-------------
|
|
|
|
To use the mbr command you must specify CONFIG_CMD_MBR=y.
|
|
|
|
Return value
|
|
------------
|
|
|
|
The variable *$?* takes the following values
|
|
|
|
+---+------------------------------+
|
|
| 0 | mbr write was succesful |
|
|
+---+------------------------------+
|
|
| 1 | mbr write failed |
|
|
+---+------------------------------+
|
|
| 0 | mbr verify was succesful |
|
|
+---+------------------------------+
|
|
| 1 | mbr verify was not succesful |
|
|
+---+------------------------------+
|
|
|-1 | invalid arguments |
|
|
+---+------------------------------+
|